Police appeal for witnesses to fatal wall collapse

Melbourne police are searching for several injured people who reportedly fled the scene of yesterday's fatal wall collapse and may be able to help with investigations.

A 30-year-old woman and 19-year-old man were crushed to death when a 15-metre-long section of brick wall at the former Carlton & United brewery site fell onto the footpath in Swanston Street in the inner city.

A 19-year-old woman who is fighting for her life in hospital had surgery for critical head injuries overnight.

Police are yet to confirm the identities of the deceased, although next of kin have been informed.

In the aftermath of the accident, Victoria Police issued several pleas for witnesses to come forward.

They are particularly keen to hear from people they believe were injured but did not stop to talk to officers.

"At this stage we're still making inquiries in relation to a large volume of witnesses," Detective Senior Constable Brooke Manly from Victoria Police told reporters.

"There are people out there that we we haven't yet identified.

"Our advice from the fire brigade is that there were others injured but those people have left the scene through fear of remaining, being that they weren't entirely sure what the incident was, whether it was a wall collapsing or something on a larger scale.

"We're asking those people to come forward, particularly if anyone else has sustained an injury or been directly involved.

"Other witnesses may have seen something else or be further able to assist us with not only witness accounts but particularly in this day and age with a lot of mobile phone devices and stuff like that, possibly footage."

It is believed unusually strong wind gusts contributed to the collapse of the wall.